1. Technical Field
The present application relates to a rotary engine, and in particular to a rotary engine that includes a structurally efficient liquid cooled rotor housing.
2. Background Information
Engines typically compress air or other gaseous oxidizers prior to adding fuel and ignition to produce power. Many examples of engines with separable positive displacement compression systems exist. One example can be conceptualized from a Wankel engine. The Wankel engine, invented by German engineer Felix Wankel is a type of internal combustion engine which uses a rotary design. Its cycle takes place in a space between the inside of an oval-like epitrochoid-shaped housing and a rotor that is similar in shape to a Reuleaux triangle but with sides that are somewhat flatter. This design delivers smooth high-rpm power from a compact size. Since its introduction, the engine has been commonly referred to as the rotary engine.
An improvement on the rotary engine uses a first rotor as a compressor to provide compressed air to a second rotor. The compressed air is then further compressed in the second rotor in advance of combustion. In some embodiments the exhaust of the second rotor is returned to the expanding section of the compressor rotor, thereby providing power recovery and increasing efficiency. This configuration has been referred to as a compound rotary engine. An example of such an engine is disclosed in U.S. Patent Publication 2010/0269782, assigned to the assignee of the present application.
Rotary engine housings suffer from structural inefficiency and non-uniform cooling, resulting in increased weight and reduced engine life as well as relatively complex and expensive castings. Specifically, the traditional rotor housing is fabricated from a single piece casting with complex internal passages for cooling fluid to flow through to provide convective cooling of the housing.
There is a need for a structurally efficient liquid cooled rotor housing for a rotary engine.